1. Technical Field
The invention relates to medical and veterinary sample collection devices and to medical and veterinary analytical devices of specialized form and function, and to integrated microfluidic devices for both sample collection and analysis. The invention further relates to a method for biohazard sample collection.
2. Description of the Related Art
The art relating to handling of swabs is well established, but remains in need of improvement, both to ensure the integrity of the clinical sample and its protection from contamination, but also to ensure that healthcare professionals are not unnecessarily or inadvertently exposed to biological material on the exterior surfaces of the swab container. Once the external surfaces are contaminated during sample collection, exposure readily occurs when a swab container is passed from hand to hand, and no on-board means is known to refresh or cleanse the outside surfaces of the sample container.
We have reviewed the patent literature, and found little or no teaching that comments on this problem. U.S. Pat. No. 4,803,998 to Kezes relates to a swab retaining vial cap and describes a combination containment vial with cap and with swab mounted inside the cap, the vial containing a medium for preserving a sample on the swab during shipment. The swab is removed from the cap to collect a sample and the swab tip can then be broken off when inserted into the vial so that the swab tip drops to the bottom of the vial without contamination by the user. The cap is then sealed. FIG. 4 shows a swab with frangible shaft. The patent is indicative of early efforts to protect a sample from contamination. This seems to accurately reflect the overall state of the art as it exists at this filing. We note that while the interior of the vial is carefully protected from contamination, the exterior is subject to contamination during handling, and becomes a fomite vector for infectious disease. Samples collected in this way are frequently removed for analysis at a separate location, and those who handle the sample container may inadvertently be exposed to material on the exterior surface of the sample container.
U.S. Pat. No. 6,991,898 to O'Connor (Jan. 31, 2006) describes a self-contained diagnostic test device for collection and detection of an analyte in a biological specimen. The device comprises a tubular swab and reagent dispensing cap. The reagent dispensing cap delivers one or more selected reagents to an assay chamber upon the rotation of the reagent chamber.
In U.S. Pat. No. 7,098,040 to Kaylor, a swab-based diagnostic test device is provided. The test device contains a reagent and a rupturable seal for adding the reagent to the sample after the swab is sealed inside the device.
U.S. Pat. No. 6,277,646 to Guirguis provides a device for both collecting and testing a fluid specimen. A fluid specimen is collected and an aliquot is transferred to an isolation chamber, from which a flow path to a test chamber is opened.
U.S. Pat. No. 6,565,808 to Hudak describes a fluid flow actuating device or structure, such as a valve, which separates the sample receiving chamber from the test platform. The test method involves collecting a sample, contacting the sample with the proprietary test device, and detecting the analyte in the sample.
U.S. Pat. No. 6,248,294 to Nason relates to a self-contained diagnostic test unit for use in the collection and analysis of a biological specimen. The test unit comprises is tubular housing for capturing a swab. A reagent dispenser cap delivers reagents to the specimen chamber and a diagnostic strip assembly is mounted on the housing so a portion of the specimen can flow by wick action through the test strip, producing a visible color change.
U.S. Pat. Nos. 5,266,266 and 5,879,635 to Nason relate to a reagent dispenser which includes a pair of reagent chambers with selected reagents therein, and a dual nib for hermetically sealing the reagent chambers. A portion of the dispenser is deformable to break or otherwise to displace the nib in a manner permitting the two reagents to flow together and mix within one of the reagent chambers. The deformable portion or the dispenser can then be squeezed to express the mixed reagents for delivery to contact the specimen to be analyzed. In a preferred form, the dispenser is a cap assembly on an open-ended tubular housing configured for receiving a swab.
Similarly, U.S. Pat. No. 6,890,484 to Bautista relates to in-line test device and describes a swab receiving port integrated into the body of a lateral flow strip. No means for protecting the exterior of the test apparatus is described. Goodfield, in Sampling and Assay Device (WO1997/23596), discloses a swab and swab container with liquid assay reagents accessible by rupture of foil liners, again with no outer disposable protective layer.
All the above devices and methods are deficient for the present purpose in that the operator is exposed to contamination of the external surfaces of the specimen collection container by contact with residues of specimen or unrelated patient-derived bodily material, which may be unhygienic and grossly objectionable. This problem is apparently not considered.
United States Patent Application 2005/0009200 to Guo relates to a sanitary and compact fecal occult blood collector kit. The swab tip in this case is covered “for hygienic purposes”. Also disclosed is a package for the swab and the cover. However, on closer study, the purpose of the cover is again to protect the sample, not the handle of the swab contacted by the operator or the external surfaces of the swab collection container, and the exterior of the package cannot be cleaned of contaminating matter that accumulates during sampling. Further, the swab must again be retrieved from the package. Thus while the sample is protected, the user is potentially exposed at multiple levels.
Miniaturizing some of the processes involved in clinical analyses, including nucleic acid, immunological and enzymatic analysis, or combinations thereof, has been achieved using microfluidic devices. Microfluidic techniques known in the art include electrophoretic detectors, for example those designed by ACLARA BIOSCIENCES® Inc., or the LABCHIP®™ by Caliper Technologies Inc, and hybridization detectors such as those manufactured by Nanogen of San Diego. Also indicative of the state of the art are PCT Publication WO1994/05414, U.S.Pat. Nos. 5,498,392, 5,304,487, 5,296,375, 5,856,174, 6,180,372, 5,939,312, 5,939,291, 5,863,502, 6,054,277, 6,261,431, 6,440,725, 5,587,128, 5,955,029, 5,498,392, 5,639,423, 5,786,182, 6,261,431, 6,126,804, 5,958,349, 6,303,343, 6,403,037, 6,429,007, 6,420,143, 6,572,830, 6,541,274, 6,544,734, 6,960,437, 6,762,049, 6,509,186, 6,432,695, 7,018,830, and 2001/0046701, 2003/0138941, and International Pat. Nos. WO 2003/004162, WO2002/18823, WO2001/041931, WO1998/50147, WO1997/27324, all of which describe apparatuses and methods incorporating various microfluidic processing and analytical operations involved in nucleic acid analysis, and are incorporated herein by reference.
Co-assigned to MICRONICS®, Inc of Redmond WA, and also incorporated herein in full by reference, are U.S. Patent No. 6,743,399 (“Pumpless Microfluidics”), U.S. Patent No. 6,488,896 (“Microfluidic Analysis Cartridge”), U.S. Patent No. 5,726,404 (“Valveless Liquid Microswitch”), U.S. Patent No. 5,932,100 (“Microfabricated Differential Extraction Device and Method”), (“Tangential Flow Planar Microfluidic Fluid Filter”), U.S. Patent No. 5,872,710 (“Microfabricated Diffusion-Based Chemical Sensor”), U.S. Patent No. 5,971,158 (“Absorption-Enhancing Differential Extraction Device”), U.S. Patent No. 6,007,775 (“Multiple Analyte Diffusion-Based Chemical Sensor”), U.S. Patent No. 6,581,899 (“Valve for Use in Microfluidic Structures”), U.S. Patent No. 6,431,212 (“Valve for Use in Microfluidic Structures”), U.S. Patent No. 7,223,371 (“Microfluidic Channel Network Device”), U.S. Patent No. 6,541,213 (“Microscale Diffusion Immunoassay”), U.S. Patent No. 7,226,562 (“Liquid Analysis Cartridge”), U.S. Patent No. 5,747,349 (“Fluorescent Reporter Beads for Fluid Analysis”), US Patent Applications 2005/0106066 (“Microfluidic Devices for Fluid Manipulation and Analysis”), 2002/0160518 (“Microfluidic Sedimentation”), 2003/0124619 (“Microscale Diffusion Immunoassay”), 2003/0175990 (“Microfluidic Channel Network Device”), 2005/0013732 (“Method and system for Microfluidic Manipulation, Amplification and Analysis of Fluids”), 2007/0042427, “Microfluidic Laminar Flow Detection Strip”, 2005/0129582 (System and Method for Heating, Cooling and Heat Cycling on a Microfluidic Device); and unpublished US Patent documents titled, “Integrated Nucleic Acid Assays,” “Microfluidic Cell Capture and Mixing Circuit”, “Microfluidic Mixing and Analytical Apparatus,” “System and Method for Diagnosis of Infectious Diseases”, “Methods and Devices for Microfluidic Point of Care Assays”, “Integrated Microfluidic Assay Devices and Methods”, and “Microscale Diffusion Immunoassay Utilizing Multivalent Reactants”, all of which are hereby incorporated in full by reference. Also representative of microfluidic technologies that are co-assigned to MICRONICS® are PCT Publications WO 2006/076567 and 2007/064635, all incorporated herein in full by reference for what they enable.
The utility and breadth of microfluidic assays for nucleic acid assays is further demonstrated in the scientific literature, the teachings of which are incorporated by reference herein. These teachings include, for example, Nakano H et al. 1994. High speed polymerase chain reaction in constant flow. Biosci Biotechnol Biochem 58:349-52; Wilding, P et al. 1994. PCR in a silicon microstructure. Clin Chem 40(9):1815-18; Woolley A T et al. 1996. Functional integration of PCR amplification and capillary electrophoresis in a microfabricated DNA analysis device. Anal Chem 68:4081-86; Burke D T et al. 1997. Microfabrication technologies for integrated nucleic acid analysis. Genome Res 7:189-197; Kopp et al. 1998. Chemical amplification: continuous-flow PCR on a chip. Science 280:1046-48; Burns, M A. 1998. An Integrated Nanoliter DNA Analysis Device. Science 282:484-87; Belgrader P et al. 1999. PCR Detection of bacteria in seven minutes. Science 284:449-50; Lagally E T et al. 2001. Fully integrated PCR-capillary electrophoresis microsystem for DNA analysis. Lab Chip 1:102-07; Tudos A J et al. 2001. Trends in miniaturized total analysis systems for point-of-care testing in clinical chemistry. Lab Chip 1:83-95; Belgrader P et al. 2002. A battery-powered notebook thermocycler for rapid multiplex real-time PCR analysis. Anal Chem 73:286-89; Hupert L M et al. 2003. Polymer-Based Microfluidic Devices for Biomedical Applications. In, (H Becker and P Woias, eds) Microfluidics, BioMEMS, and Medical Microsystems, Proc SPIE Vol 4982:52-64; Chartier I et al. 2003. Fabrication of an hybrid plastic-silicon microfluidic device for high-throughput genotyping. In, (H Becker and P Woias, eds) Microfluidics, BioMEMS, and Medical Microsystems, Proc SPIE Vol 4982:208-219; Anderson R C et al. 2000. A miniature integrated device for automated multistep genetic assays. Nucl Acids Res 28(12):[e60, i-vi]; Yang, J et al. 2002. High sensitivity PCR assay in plastic micro reactors. Lab Chip 2:179-87; Giordano B C et al. 2001. Polymerase chain reaction in polymeric microchips: DNA amplification in less than 240 sec. Anal Biochem 291:124-132; Khandurina J et al. 2000. Integrated system for rapid PCR-based DNA analysis in microfluidic devices. Anal Chem 72:2995-3000; Chiou, J et al. 2001. A Closed-Cycle Capillary Polymerase Chain Reaction Machine. Anal Chem 73:2018-21; Yuen, P K et al. 2001. Microchip module for blood sample preparation and nucleic acid amplification reactions. Genome Res 11:405-412; Zhou X, et al. 2004. Determination of SARS-coronavirus by a microfluidic chip system. Electrophoresis. 25(17):3032-9; Liu Y et al. 2002. DNA amplification and hybridization assays in integrated plastic monolithic devices. Anal Chem 74(13):3063-70; Zou, Q et al. 2002. Micro-assembled multi-chamber thermal cycler for low-cost reaction chip thermal multiplexing. Sensors Actuators A 102:224-121; Zhang C et al. 2006. PCR Microfluidic devices for DNA amplification. Biotech Adv 24:243-84, and Zhang, C and Xing D. 2007. Miniaturized PCR chips for nucleic acid amplification and analysis: latest advances and future trends. Nucl Acids Res 35(13):4223-37.
Thus there is a clear and ongoing interest in microfluidic devices for clinical and veterinary diagnostic assays. As these commercial applications increase, the world-to-chip interface is receiving increasing attention, and we note that little has been done in the area of sample collection to both improve the validity of nucleic acid amplifications by preventing cross-sample contamination, and just as importantly, to prevent exposure of those persons handling the specimens to objectionable or potentially infectious materials. As has been noted, (Nelson, D. B. et al. 2003. “Self-Collected Versus Provider-Collected Vaginal Swabs for the Diagnosis of Bacterial Vaginosis: an Assessment of Validity and Reliability,” J Clin Epidemiol, 56:862-866), there is an increasing trend toward patient self-collection of samples, often with swabs or cups. Typically the patient is not provided with means to ensure that the external surfaces of the sample collection device does not become contaminated with the sample or related biological fluids during handling. These swabs or cups are typically then processed or handled by ungloved couriers and paraprofessionals and must then be transferred to the analytical device or further handled and processed by nursing and laboratory personnel. The sample collection device thus becomes a fomite potentially capable of spreading infectious disease to numerous persons, and a method or means for eliminating or at least reducing the exposure of health workers to the contaminated exterior of the sample collection vials, bottles, cups, tubes, and so forth, has been a longstanding and unmet need in the healthcare industry.
Furthermore, awareness of the dangers of unsafe handing of biological fluids and specimens has increased dramatically in the last two decades, and single-entry devices are increasingly needed that seamlessly integrate sample preparation, extraction, and analysis without unnecessary operator exposure. A further objective we have identified is the need to fully integrate the device into a disposable format, so that once a sample is collected, either by patient or by a health professional, all remaining steps of the analysis, up to and including display of the result, are performed without further personal exposure to the sample. A critical step in this process is thus the refreshing or disinfecting of the external surface sample collection container (whether it is also the analytical device or not), and to our knowledge, satisfactory solutions to this problem have not been recognized or brought forward prior to our disclosure herein.